This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
The stirring, or mixing, stick shown in the sketch deserves its name, as it will stir evenly all the way around. It consists of two flat sticks, one two-thirds the width of the other, which are nailed together as shown. The narrow one is only long enough to enter the depth of the liquid. - Contributed by Frank J. Rempe, Oakland, California.
Ill: A Flat Surface Strikes the Liquid No Matter Which Way the Stick is Moved